1. Field of the Invention
The present invention relates to a heat sink unit for cooling semiconductor devices such as IC, LEI, MU, and the like and electronic components. The invention also relates to an electronic apparatus using the same.
2. Description of the Prior Art
FIG. 7 is a plan view showing a heat sink unit of the prior art, and FIG. 8 is a cross sectional view also showing the heat sink unit of the prior art. In FIG. 7 and FIG. 8, the conventional heat sink unit comprises a heat sink substrate 1, a motor 2 disposed on the heat sink substrate 1, a fan 3 rotated by the motor 2, an intake opening 5 formed in a cover 4, an exhaust opening 6 for blowing out a gas flow into one direction, and a fin 7 disposed to the heat sink substrate 1 for dissipating heat.
The heat sink unit constructed as above is attached to a semiconductor device such as MPU mounted in a computer, and the like, to dissipate heat generated by the MPU, so as to prevent the MPU from falling into thermal runaway and the like failure.
However, amount of heat generated by the semiconductor devices such as MPU is increasing by a improvement of their performance. There were such problems as larger noises due to an interaction of the fan 3 with air when rotation speed of the motor 2 is increased in an attempt to improve cooling effect, and a cooling efficiency remains low because an amount of air-flow does not increase so much even when the motor 2 is rotated at a high speed.
This is attributed to the structure in that the fan 3 draws air from a side of the cover 4, and blow out the air through the exhaust opening 6 located in a direction generally orthogonal to the incoming air flow. For this reason, the MPU could not be cooled sufficiently, a gas circulation within an enclosure was poor, and it was difficult to lower a temperature within the enclosure.
The present invention addresses the problems described above, and it aims to provide a heat sink unit having outstanding cooling performance and an electronic apparatus using the heat sink unit.
A heat sink unit of the present invention comprises:
a substrate;
a fan for supplying a gas flow to the substrate;
driving means for rotating the fan;
a fin composed as a separate body from the substrate and attached to the substrate; and
a cover providing a space between the substrate and the cover and attached to the substrate,
wherein the fan, the driving means and the fin are arranged within the space, the cover has a first opening in a section facing the fan, and
the substrate and the cover form a second opening at a side next to the fin.
In the heat sink unit of the present invention, an opening for mounting the fin is provided in the substrate between the fan and the second opening, and the fin composed of a material different from the substrate material is attached to the opening in the substrate.
Furthermore, a heat sink unit in another embodiment of this invention is so constructed that a height from a bottom surface of the substrate to an upper surface of the cover at a section where the fin is disposed is higher than that at another section where the fan is mounted, and that a thickness of a base of the fin is larger than a thickness of the substrate.
In addition, an electronic apparatus of the present invention has a heat sink unit of the present invention disposed within the apparatus.
With the structure, the present invention can provide the heat sink unit and the electronic apparatus having large cooling performance.